Lessons are used to organize course content by weeks, units, or whatever organizational structure works for your course. With Lessons, you are essentially creating a linear flow of what you would like your students to do. Once you create Lessons, you can add content items, set prerequisites, and add requirements.
Once you have a Course selected in the Courses and Groups dropdown menu, click the Lessons link in the Course Navigation bar.
Click the Add Lesson button.
Add Lesson Name
Type a name in the Lesson Name field.
Lock Lesson Date
If you want to lock the Lesson until a specific date, click the Lock until checkbox. Then select a date and time on the Calendar.
Add Lesson Prerequisites
If you have added at least one Lesson to your course, you can require a prerequisite Lesson. A prerequisite Lesson means students must complete the added Lessons before they can view the new Lesson. To add a Lesson prerequisite, click the Add Prerequisite link.
In the Prerequisite drop-down menu , select the Lesson that should be completed before the new Lesson.
To add additional prerequisite Lessons, click the Add Prerequisite link  again.
Click the Save button  to add your Lesson to the Course.